The consumer backlash against Toyota intensified tonight when drivers of the recalled Prius complained that the ­company had allowed the vehicle's brake fault to go untreated for months and claimed Toyota is wrong to say the ­problem does not affect safety.

Anger at the world's largest carmaker's handling of mechanical and design faults grew as Toyota bosses said they are recalling 437,000 third-generation Prius cars because of brake faults, 8,500 in the UK.

Owners of the Prius, a leader in the "green" motoring sector, said the brake fault occurred in vehicles up to six months ago and has caused cars to overshoot at roundabouts and junctions, an experience they describe as scary and dangerous. A software fault in the anti-lock braking system means the brakes lose power momentarily on rough or slippy surfaces.

Toyota today lodged a "non-safety" recall with the Department for Transport's Vehicle and Operator Services Agency, and said there is no danger to drivers. From Thursday it is planning to start reprogramming computers of the affected cars to prevent the problem happening again. The latest recall means more than 8.5m Toyotas worldwide have been called back for servicing since the end of January.

In a statement issued this morning, Toyota GB apologised to its Prius ­customers for the brake problem and insisted: "The cars are safe to drive … At no time are drivers without brakes."

But owners of affected third-­generation Prius models, on sale since last August, accused Toyota GB of under­playing the danger. "When I go over a road hump at 25mph the brakes cut out and it feels like you have hit a patch of ice," said David Meredith, a teacher from Tamworth in Staffordshire who has had the problem since last September. "It happens all the time. But ­Toyota have handled this really badly. When your car doesn't stop when it should do, it is surely a safety issue."

"They are bound to want to say that [it is not a safety issue], because this is their flagship car, but it definitely is," said a London banker who suffered a brake failure last October. "If there was a car on the other lane when the brakes failed on my car, I would have crashed into it."

The Prius recall is seen as striking at the heart of Toyota's brand values. "The Prius is one of the world's most brilliant cars," said motoring critic Quentin Willson. "It has done so much to educate people about low emissions cars. It is such a shame it has been besmirched."

With an estimated $4bn (£2.5bn) wiped off Toyota's market value by the crisis, Akio Toyoda, the company's president, made his second public appearance in Tokyo. He said Toyota "will face up to the facts and correct the problem, putting customers' safety and convenience first".

But Toyota suffered another blow tonight as US safety officials said they are investigating about 80 complaints of steering difficulties from drivers of 2009 and 2010 Corollas. Many say their cars can wander when they drive on the highway, making it hard to stay in lane.

In the UK, the chairwoman of the House of Commons transport select committee, Louise Ellman, accused Toyota of issuing "sketchy" statements and questioned how long the manufacturer knew about the ­Priius problems before it went public.

"There is a great deal of anxiety and some of it is justified," she said.

"It is not clear when Toyota became aware of these issues and how quickly they transmitted it to the public. I think their statements have been sketchy and they are now reacting to events," she said. "They need to give more confidence to the public that they are being full in what they are saying."

Toyota GB has said it knew about accelerator problems, which have caused its cars to speed up suddenly, from the end of 2008, but could not say when it received first reports of the Prius brake problem.

State Farm, America's largest car insurer, today said it warned federal safety regulators about a rise of reports about the accelerator fault in late 2007.

Toyota in America is set to come under more pressure when the company's US head, Yoshimi Inaba, appears before a congressional committee tomorrow.Japan's transport minister is due to meet with the US ambassador to Japan, John Roos, to discuss the problems.

There was also anger at Toyota's refusal to admit a recall of the Prius was imminent in recent days.

Ben Howard, a TV editor from London, ordered a Prius early last month, but after hearing about the problems he was assured by his Toyota dealer that "there is no recall and that it doesn't affect your car".

On ­Monday, ­having collected his new Prius, he learned that it would be recalled after all.

"I feel Toyota was more interested in getting us to take that car off the forecourt than waiting to investigate if there was an issue that would affect it a week later."

Workers at Toyota's Burnaston plant in Derbyshire where the Avensis and Auris are manufactured, said tonight they are concerned that the crisis could hit jobs.

Tom Sawyer, Unite's regional officer for Toyota's Burnaston and Deeside plants, said: "What adds to the concern is that with the company coming out of recession this could hinder that recovery and this could have a consequence in terms of orders."